In the Upper Midwest, some corn growers saw tar spot in regions where they didn’t anticipate it. Dry conditions didn’t eradicate the problem completely.
FMC Corporation says growers need to consider tar spot as they plan for the 2024 season – you never know if you’ll get the perfect conditions for that disease to cause problems.
Gail Stratman, regional technical manager with FMC, manages agronomists across the Midwest. He advises Wisconsin corn growers on how to fit fungicide into their 2024 crop protection plan based on what he’s heard this year.
He reminds growers that tar spot likes conditions in the upper 60-80 degree areas. The disease also develops well under 8-10 hours of leaf wetness. High humidity paired with a cool night creates dew and moist conditions.
“One of the issues that they’ve shown in some places is even irrigation can promote this,” he warns.
Stratman explains agronomists are learning more about tar spot every year. When the disease first got going, he said everybody thought it would stay in the East because it likes cool and damp conditions. But he’s found tar spot has moved West and North, despite the drier environments.
“It’s been more resilient than people have given it credit for,” he says. “But it also has taught us that we can manage this disease if we use some good practical disease management practices. Understand what our fungicides can and can’t do, and when to utilize them. We’re seeing some really, really good results, and growers have been able to manage the disease pretty effectively.”
